A thin-film structure includes plate-shaped metals or plate-shaped structures in which a plate-shaped metal and a plate-shaped dielectric are in contact. The plate-shaped metal or structures are formed on a transparent base having a surface with line-shaped corrugated structures. The plate-shaped metals or structures are perpendicular to or oblique to the surface of the base. The thin-film structure has characteristics suitable for polarizers used in liquid crystal projectors and the like.